Long adult deformity fusions to L5 and the sacrum. A matched cohort analysis

Spine (Phila Pa 1976). 2004 Sep 15;29(18):1996-2005. doi: 10.1097/01.brs.0000138272.54896.33.


Study design: A matched cohort analysis of long adult deformity fusions according to distal fusion level (L5 vs. S1). OBJECTIVE.: To compare the results of long adult deformity fusions to either L5 or the sacrum in the presence of a "healthy" 5-1 disc using a matched cohort analysis.

Summary of background data: For adult spinal deformity, the decision often arises whether to terminate a long fusion at L5 or the sacrum. The decision is especially challenging in the presence of a "healthy" (Grade 0 to 1 degeneration) 5-1 disc.

Materials and methods: A total of 95 adult deformity patients that underwent fusion from the thoracic spine to either L5 or the sacrum were sorted according to five preoperative criteria: 5-1 disc status, patient age, smoking status, number of levels fused, and sagittal balance. Two cohorts (L5, 27 patients; sacrum, 12 patients) were precisely matched according to the five criteria. Patients were evaluated at 2-year minimum follow-up according to radiographic data, complications, and SRS-24 outcomes.

Results: Correction of sagittal imbalance was superior for sacrum patients (C7 plumb line: L5, 0.9 cm; sacrum, 3.2 cm; P = 0.03). At latest follow-up (L5, 5.2 years; sacrum, 3.7 years), 67% of L5 patients had radiographic evidence of advanced 5-1 disc degeneration and the L5 cohort tended to have inferior sagittal balance (C7 plumb line: L5, +4.0 cm; sacrum, +1.2 cm; P = 0.06). The sacrum cohort, however, required more surgical procedures (L5, 1.7; sacrum, 2.8; P = 0.03) and experienced a greater frequency of major complications (L5, 22%; sacrum, 75%; P = 0.02), including nonunion (L5, 4%; sacrum, 42%; P = 0.006) and medical morbidity (L5, 0%; sacrum, 33%; P = 0.001). SRS-24 scores reflected a similar patient assessment of outcome and function for the two cohorts (L5, 89; sacrum, 87).

Discussion and conclusion: At 3 to 5 years' mean follow-up, long adult fusions to the sacrum required more procedures and had a higher frequency of complications than similar fusions to L5. For fusions to L5, subsequent subjacent disc degeneration is common and may be associated with a forward shift in sagittal balance. The ultimate influence of these factors on long-term outcomes remains to be seen.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adult
  • Cohort Studies
  • Discitis / epidemiology
  • Discitis / etiology
  • Discitis / pathology
  • Female
  • Follow-Up Studies
  • Humans
  • Lumbar Vertebrae / diagnostic imaging
  • Lumbar Vertebrae / surgery*
  • Male
  • Middle Aged
  • Missouri / epidemiology
  • Motion
  • Osteoarthritis / epidemiology
  • Osteoarthritis / etiology
  • Osteoarthritis / pathology
  • Patient Satisfaction
  • Postoperative Complications / epidemiology
  • Postoperative Complications / pathology
  • Preoperative Care
  • Pseudarthrosis / epidemiology
  • Pseudarthrosis / etiology
  • Pseudarthrosis / pathology
  • Radiography
  • Retrospective Studies
  • Sacrum / diagnostic imaging
  • Sacrum / surgery*
  • Spinal Fusion / methods*
  • Spinal Fusion / statistics & numerical data
  • Treatment Outcome